1. Technical Field
The present invention relates to a method of manufacturing a microlens, a microlens, an optical film, a screen for projection, a projector system, an electrooptical device and electronic equipment.
2. Related Art
Various display devices (electrooptical devices) are equipped with color filters in order to display in color. The color filter consists of a substrate made of, for example, glass and substrate, and filter elements colored with various colors such as red (R), green (G) and blue (B) and fabricated on the substrate in the form of dots. The filter elements are arranged in a certain pattern such as so-called stripe, delta and mosaic arrangement on the substrate.
The electrooptical device including a liquid crystal device and an electroluminescence (EL) device as a display has display dots arranged on a substrate of such as glass and plastic. An optical state in each display dot is independently controllable. In the case of the liquid crystal device and the EL device, liquid crystal or an EL light emitting part is provided in each display dot. The display dots are typically arranged in, for example, a latticed pattern (a dot matrix pattern).
The display dot (the liquid crystal or the EL light emitting part) is formed corresponding to each color, such as R, G and B as described above in a display device so that the device is capable of displaying in color. One pixel consists of a group of the display dots in order to display all the colors. For example, the group comprises three display dots. The color display is performed by controlling a tone of each display dot in the pixel.
As for a liquid crystal device, a microlens is typically provided in a backlight for a liquid crystal display that is embedded in the liquid crystal device, so that light from a light source in the backlight is effectively collected by the liquid crystal elements. JP-A-2005-62507 is a first example of related art. There are many reports including the first example about a method of fabricating the microlens by using a droplet discharge method. In a typical fabrication of a microlens by the droplet discharge method, an aspect ratio and a curvature of the microlens depends on a contact angle of a droplet discharged to form the microlens to the substrate. However, it is difficult to heap up the droplet beyond the contact angle. For this reason, a pinning effect (with which a droplet is retained by a step) utilizing a bank is required in order to improve the aspect ratio.
JP-A-2003-258380 is a second example of related art. As described in the second example, the bank is formed so as to surround a lens formed part by photolithography. JP-A-2001-141906 is a third example of related art. According to the third example, a liquid-repellant patterned film is formed as an alternative to the bank. JP-A-2004-338274 is a forth example of related art and JP-A-2004-341315 is a fifth example of related art. According to the forth and fifth examples, a foundation is formed by the photolithography.
In the manufacturing processes of the structures described in the examples, there are exposure steps and development steps. Masks are used in the exposure steps and developer is used in the development steps. Accordingly, the overall manufacturing process becomes insufficient. In other words, the hitherto known manufacturing methods did not fully utilize the advantages of the droplet discharge method.